Wednesday, February 06, 2008

Pump gun scope mounting tips

by B.B. Pelletier

We received this as a review several days ago, but it's really a procedure for mounting a scope on a pneumatic rifle or pistol. It was submitted by a customer named Greg. Here's what he has to say:

I"ve been shooting Benjamin/Sheridan Streak rifles and EB/HB pistols for over 25 years...all of which have been scoped with one optic or another! I think that I can help with mounting your scope so that it's rock solid stable on any of these or the 392/397 rifles. Believe it or not, there's a method of mounting that makes the new 4-piece mounts even more stable than the old 2-piece mounts...and I have experience with scoping dozens of each many times over.

The process follows...

Buy a 1-piece ring mount kit in the diameter and height you require for your optic. I recomend the Leapers Accushot high mount. Next, buy the Crosman 4-piece intermount.

When installing the 4-piece mounts, spread them apart on the barrel so they're the same width as your Accushot mount. Before you install them on the barrel, purchase thick 2-sided tape. Cut a small tab from the tape that's the same width as the 4-piece intermount and long enough to wrap around the barrel. Install the 4-piece mount over the tape and snug down the screw but do NOT over-tighten!

Place your 1-piece ring mount onto the intermount, making sure that they're the same width apart.

The next step is vital! When you snug the screws on your 1-piece mount (there are 3 or 4, depending on which brand you choose)...lightly snug down the end screws over the intermount, then tighten the center screws firmly. The final step is to go back and tighten down the end screws over the 4-piece intermount. Be sure to follow this order!

Install your scope, tightening the cap screws firmly but not too tightly. Remember, your rifle is a pneumatic and does not recoil. Now, you can sight in your rifle and enjoy it.

If you use this method your scope will never move, and it will also be solid. It also looks better!

Hope this helps. Enjoy your shooting.

Thank you, Greg, for that tip. And for those who want a solid mount that fits over the receiver, don't forget the Air Venturi intermount.

32 Comments:

At February 06, 2008 9:38 AM, Anonymous jagxke said...

Hi Tom,
This is off the subject but since you have had a hand in the development of Benjamin Discovery and the Talon SS, given the difference in price, is one a better value than the other?
Thanks,
Jeff

 
At February 06, 2008 11:05 AM, Blogger B.B. Pelletier said...

Jeff,

The Benjamin is better for breaking into PCPs because of the price. That Talon SS has many more advantages of barrel interchangability . So take your pick.

Accuracy is equivalent between both rifles.

B.B.

 
At February 06, 2008 11:14 AM, Anonymous Jim in KS said...

B.B. -

I don't have a Benjimin/Sheridan airgun that would require this method of scope mounting, but I am interested in getting an IZH-60 if they ever become available again. If I find one, I'll want to mount a scope on it. They present a very similar challenge to the Benjis when it come to mounting a scope.

Recently, there was a very good post on the yellow forum about using the Air Venturi intermount on the IZH-61. Instead of double sided tape, he used thin guitar picks as shim material between the barrel and the intermounts. He said that it was very sturdy. The images of his rifle looked really good. The full-sized scope was in the proper position and the entire rig looked like it was made that way.

By the way, have you heard if Pyramid will be getting any more IZH-60's anytime in the forseeable future?

- Jim in KS

 
At February 06, 2008 11:29 AM, Blogger B.B. Pelletier said...

Jim,

The EAA folks didn't seem interested in the IZH 60, so I don't think they will come in soon for that reason, but PA had had some on order for a while, and they may be here soon.

B.B.

 
At February 06, 2008 11:31 AM, Anonymous PA Gunner said...

b.b.
sorry to bug you if your still away, but iv an important question. i was shooting pellets with my viper xpress, and i noticed that the stock is loose enough for me to see the action, barell and scope mount shifting every time i cock it. im assuming its the stock screws are loose, but i cant find them. do you have any advice? thanks

 
At February 06, 2008 11:35 AM, Blogger B.B. Pelletier said...

PA Gunner,

Pry up the rubber inserts on either side of the forearm and the torx screws are there.

B.B.

 
At February 06, 2008 11:44 AM, Anonymous PA Gunner said...

thx!

 
At February 06, 2008 12:12 PM, Anonymous Anonymous said...

B.B.,
A while back you wrote an article on how the air pressure regulator works inside a PCP. I don't see how a PCP can shoot consistently without a regulator and I also like to know how one can tell whether or not a PCP has a regulator just by its appearance. The reason I am asking is that all the PCP specs posted by Pyramyd don't mention pressure regulator at all. Thanks.

Alan

 
At February 06, 2008 12:42 PM, Blogger rimugu said...

Another vote for IZH 60. Have been waiting for it since last year. I will keep checking weekly for another year just in case.

 
At February 06, 2008 12:57 PM, Anonymous Anonymous said...

Thanks for this post. I recently installed a 'scout scope' on the barrel, using intermount, using Weaver 49515 rings (iron sight useage retained) and NCStar 2-7x variable pistol scope (has very short eye relief but no AO capability) - this should be very useful for keeping it tight.

 
At February 06, 2008 1:02 PM, Blogger B.B. Pelletier said...

Alan,

Here's an analogy about unregulated airguns. Your car will go just as fast on one gallon of gas as it will on a full tank.

Many of the guns Pyramyd Air sells are not regulated, but we will look into the matter. Many manufacturers are getting away from regulators because they are somewhat unreliable, but there are still regulated guns on the market.

B.B.

 
At February 06, 2008 1:07 PM, Blogger B.B. Pelletier said...

rimugu,

I will let you readers know when the 60 comes in. Please act fast, because they sold out in days about 6 month ago.

B.B.

 
At February 06, 2008 2:23 PM, Anonymous Anonymous said...

Jim in KS,

Here's a link to the post on scoping the IZH61.

http://www.network54.com/Forum/275684/thread/1198129613/

Regards,
Michael in Florida

 
At February 06, 2008 2:36 PM, Anonymous Anonymous said...

I'm wondering if the Crosman intermounts would work OK on a Crosman 180 Pellgun...I mic'd the barrel @ .560 inches - the dia. is the same from muzzle to rear end of it.

Is the Benji/Sheridan barrel close to this dimension?

Jim Duda
Austin, TX

 
At February 06, 2008 2:46 PM, Blogger Michael in Florida said...

Jim,

The Air Venturi Intermount will adjust from 0.540 to 0.556.

Regards,
Michael in Florida

 
At February 06, 2008 2:50 PM, Anonymous Jim in KS said...

Michael in Florida -

That's the post that I was referring to. Very stylish rig you've got there. How does it shoot?

- Jim in KS

 
At February 06, 2008 4:37 PM, Anonymous Anonymous said...

To those wanting to scope the IZH 60/61. If you get a Leapers Bug Buster scope and medium accushot rings, it will all just fit onto the scope rail, and mine has remained solid. And if you open the buttstock so that you move the anchoring screw and get the full extension, you should have no problem with eye relief. B.B.'s part 1 of his IZH 61 blog describes how to extend the stock.

A question about the difference between the 60 and 61. I know that single shots are supposed to be more accurate because the pellet is loaded directly into the breech and because the receiver is supposed to be more solid. But, the IZH 61 has a loading rod that pushes each pellet up into the barrel as part of the cocking cycle. Once it is pushed up the barrel like this, isn't the pellet in the exact same situation that it is in the 60 version and shouldn't the rifles then be equally accurate?

Matt61

 
At February 06, 2008 5:33 PM, Anonymous sumo said...

matt61,

Im not sure but i think...

the key is in the handling or the pellet. Its just more likely to damage the pellet with a repeater. With the same mechanism pushing the pellet in the handling of the pellet should be equal. The thing it that there is better alignment with the probe, pellet, and barrel with single shot guns. The pellet is handled more with a multi shot than single but i doubt the accuracy difference is great, if measurable in that gun(s).

If i were to get one the ONLY question i would ask is if i want a single or multi shot gun!

-sumo

 
At February 06, 2008 5:57 PM, Anonymous sumo said...

bb,

i just listened to your podcast. I have this nifty thing that measures wind speed. I use it for the long shots. I find that on those days with wind were you have to squint you shouldn't hunt. A good thing to do is improve your windy shooting ability. I got a squirrel at 117 yards a while ago and im sure i told you all about it. Anyway, i did not take the wind into account for that shot. I couldn't feel it (the wind) and neither did the squirrel (the pellet). Even with "no wind" i thing it pushed the pellet. I was aiming for the head and hit neck. Head and neck brings me to a funny story. I was prairie dog hunting with this fellow who is a bit witty and there is one 703 yards away. He says "head or neck?" i wanted to strangle him. I keep it in waiting for him to hit the dirt a couple feet away and say neck. No suck luck, ON MY PART, he nailed it in the neck at 703 yards with a 243. i didnt believe it until 10 minutes on a mule to go out and see. DEAD DOG! That was when i got into long range shooting.

-sumo

 
At February 06, 2008 6:23 PM, Blogger B.B. Pelletier said...

Matt61,

When there is a steel probe, there is also a transfer port at 90 degrees to the pellet. In a single-shot without a bolt probe the transfer port is often behind the pellet, so the air hits it square in the tail. However, in the case of the 60 I believe there is a probe, so no difference in loading.

B.B.

 
At February 06, 2008 6:27 PM, Blogger B.B. Pelletier said...

Sumo,

At 703 yards I'm not sure I could SEE a prairie dog through a scope! If I hit one, he would have to be exceptionally unlucky.

B.B.

 
At February 06, 2008 8:56 PM, Anonymous Shooter said...

703 yards! Sheesh... I'm gonna have to breakout the astronomy gear.

/Shooter

 
At February 06, 2008 9:02 PM, Anonymous sumo said...

he had a night force scope zoomed at 42x. I had my 22-250 but he suggested i use his guns. To clarify, he hit it NOT me. Luck had nothing to do with it, he could do that ALL DAY.

Thats a LONG shot to hit a 2 inch target, and he hit it in the center of its neck, it punched a clean hole. The smaller calibers blew them to bits. He said that the 243 "bucks the wind" better than the lighter calibers, as you said in your podcast. We only took a few shots off the bench because it was a windy weekend so we took most shots off of the roof of Kawasaki mules with smaller calibers. He has guns for much further ranges such as a 300 win mag but again, to windy for bench shooting.

This trip was what got me into ranges further than 300 yards. the dials on the scope started to mean something! LOL.

That was his second most amazing shot. The other was at 40 yards. He shot a jack rabbit in the neck (again with the neck) with the scope on 5.5x (it was a 5.5-22) did i mention it was on a dead run when he shot it. This guys a machine! I think it was a 222 fireball this time (yes he has both 221 and 222). He gave me a target shot from 100 yards with his ackley 22-250 and i said "so its a piece of paper with a bullet hole in it" or some thing like that (its been 3 years) and he said "no its a piece of paper with three bullet holes in it". The group was to tight i could not distinguish any individual shots.

He sent me home with a stack of books on everything you can know about rifles, now here i am today.

-sumo

 
At February 06, 2008 9:52 PM, Anonymous DB said...

Greg & B.B.,
Thanks for the Bengi scope mounting tips. Those are tough to get lined up and keep tight.

DB

 
At February 07, 2008 9:09 AM, Anonymous Anonymous said...

Alan,
In a properly designed PCP, the return spring on the valve and the striker and are sized so the velocity starts slightly low, reaches a peak velocity and drop slightly again over a wide range of shots. This works because the pressure in the reservoir creates force on the valve along with the valve spring. when the pressure is high, the valve only opens a little, letting a small amout of very high pressure air behind the pellet. As the pressure decreases, the valve opens more and lets a larger amount of lower pressure air behind the pellet. There is a peak velocity if you plot shots verses velocity on a properly designed gun. I have an S400 extr by AirArms. It shot 950 ft/sec out of the box and the velocity dropped in a straight line. I changed the springs so it shots 840ft/sec at 2600 psi charge, increases to 850 after 25 shots and drops back to 840 at 50 shots. The repeatability is amazing.
M.E.

 
At February 07, 2008 6:55 PM, Anonymous Shooter said...

Greg and BB,

Great post, finally got to read it. I don't have a Benji currently, but have been thinking I should get one just because they are classic. Now I know the stuff to use to get a scope on it when one finally shows up in my small collection.

/Shooter

 
At February 07, 2008 6:58 PM, Anonymous Shooter said...

Sumo,

Thanks for the interesting story. Some people just have that inate control that can be developed to a high degree. I'm not one of them... But that doesn't stop me from trying anyway and having a ball doing it!

/Shooter

 
At February 07, 2008 10:30 PM, Anonymous sumo said...

shooter,

i have tons of stories. Like shooting a groundhog while its under the ride home or a deer taken at 130 yards with a .22 hornet head shot. Im not a killing machine like the guy i was telling you about (nor would i want to be) but i have stories.

did you know there was a hunting club that did duck or pheasant drives by filling a bus with birds and driving around a mountain on a road with a series of speed bumps to get them out? LOL

one cool thing i can do is throw knives, assuming thats cool. LOL

-sumo

 
At February 08, 2008 8:33 PM, Anonymous Shooter said...

Sumo,

I'd have to see this bird bus with speed bumps! Where do they have that? It'd almost be worth the price just to watch that!

/Shooter

 
At February 08, 2008 8:43 PM, Anonymous sumo said...

shooter,

as i said, a story, a second hand one at that but I shot the deer first hand!

-sumo

 
At May 26, 2008 1:23 PM, Anonymous Anonymous said...

Hi there,

I have 2 questions about sights for a new Benjamin-Sheridan (Crosman?) 392.

First, how do the Williams peep sights compare to a properly mounted scope?

Second, I've read somewhere that the Air Venturi Intermount is recommended for the 392/297, but that it does not provide a standard-size dovetail, but one that will only accept a manufacturer-specific set of rings. Is this true? Or does it provide a standard 3/8" (or 11 mm) dovetail?

Thanks for your thoughts.

 
At May 26, 2008 2:32 PM, Blogger B.B. Pelletier said...

The most accurate non-optical sight is an aperture or peep sight. A scope increases the accuracy of that sight by as much as 50 percent. It depends on the target, the distance and the lighting conditions.

The Air Venturi intermount uses rings with a Weaver base. Weaver bases are not manufacturer-specific, despite the name. They are far more common than 3/8" or 11mm bases. In fact, they are the most popular scope bases on the market.

B.B.

 

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